The embodiments described herein relate to vehicle steering columns and, more particularly, to a locking assembly for vehicle steering columns, as well as a method of manufacturing the locking assembly.
Lock assemblies are employed with steering column assemblies for anti-theft purposes, among others. Some lock assemblies include a shaft surrounded by a lock sleeve. The lock sleeve includes detents that accommodate engagement of a pin or the like within one of the detents to prevent rotation of a steering column shaft line, and therefore a steering wheel. One or more intermediate components, such as one or more rings, are disposed between the shaft and the lock sleeve to establish a slip clutch that provides a “fusible link” of the components. Upon engagement of the pin or the like within one of the detents, the lock sleeve is prevented from rotating based on friction between the components of the lock assembly. However, if a torque is applied to the steering wheel, and hence the steering column shaft line, above a threshold torque, the interface between the intermediate component (e.g., ring) and the shaft begins to slip. This avoids damage to the steering column.
Unfortunately, some lock assemblies exhibit inconsistency and unpredictability based on slippage at different torque values. It is important to maintain a reliable and predictable torque at which slippage occurs. The undesirable drawbacks are exacerbated when the shaft is formed of certain materials, such as aluminum, for example.